1. Field of Invention
The present invention relates to a mandrel-locking unit having a mandrel-mounting element that has a hollow body and that accommodates therein a bearing for mounting a print roller mandrel. A pressurizing medium cylinder has a pressure chamber and a piston located therein for sliding the mandrel-mounting element between a mounting position and a release position.
2. Description of the Prior Art
The processing of different print jobs frequently necessitates the replacement of printing plates. Therefore print rollers are known from the prior art that comprise print roller mandrels whose print roller sleeves, the so-called sleeves—can be pulled off and put back on again. In order to replace the sleeves without having to remove the print roller from the printing machines, the print roller mandrels are arranged such that their one end usually floats. The free end is embraced by a bearing during the printing operation. Within the framework of the present invention, all rollers involved in a printing process are referred to as print rollers.
The patent application DE 197 05 369 A1 illustrates, for example, a printing machine of such type. A bearing block is assigned to every roller involved in the printing process. The bearing block can be displaced in relation to the roller after the connection of the bearing to the roller is released. The actual bearing is located in a bearing head that can be displaced using guides extending parallel to the axis of the roller. The process takes place by means of a piston cylinder unit. The unit consisting of the bearing, the mandrel-mounting element, the guides, and the piston cylinder is often also referred to as mandrel-locking unit.
However, the disadvantage of this design is that the mandrel-locking unit has an overall depth that results from its design and that is composed of the depth of the bearing piston and the maximum stroke of the piston cylinder unit. This overall depth brings about a space requirement on the operating side of the printing machine. This space requirement has a restrictive effect on the comfortable operability of the printing machine.
The patent application U.S. Pat. No. 3,147,702 suggests a similar mandrel-locking unit in which, however, it is not the bearing, but instead the roller journal that is pulled off from the roller. The shaft journal is thus a component of the mandrel-locking unit. In this arrangement, the shaft journal is surrounded by the piston that is designed as a hollow space. However, this mandrel-locking unit also exhibits the disadvantage of a large overall depth.